It's not enough to have a trailblazing business idea anymore. Between 80% and 90% of startups fail, according to several studies. Even ones that seem destined for success — those that have millions in funding and are backed by passionate entrepreneurs — can still collapse.

While startups fail for all sorts of reasons, there are five reasons that pop up over and over, including a lack of direction and an ineffective marketing strategy. If you're starting your own company, avoid these five common startup mistakes at all costs.

1. Lack of direction.

It's great to hire talented, excited, and ambitious people for your startup — after all, company culture is very important — but you also need to have people with experience who can guide your company toward long-term success. Sprinkle in a few seasoned employees who understand the nuances of growing a business from the ground up.

2. The wrong technology.

Some startups fail to understand their target audience and how they use technology. For instance, if you're creating an online source for retirees, then you have to recognize they would most likely prefer talking to a person instead of, say, text messaging or video conferencing. You can still add those features, but always take your audiences' tech habits into consideration when creating a product or service.

3. Putting all your eggs in one basket.

Does your startup have tunnel vision? Many startups fail because they take an all-or-nothing approach, therefore alienating potential investors, when they should be willing to adapt and diversify. If you have one great product that is bound to sell, ensure there will be more happening down the road.

4. Not having the right goals from the start.

Go big or go home, but don't go too big or it could all come crashing down. You don't want to expand too quickly, but you don't want to move at a snail's pace either. Make sure your business is growing steadily by planning where you would like it to be a month, year, and even five years from now. Constantly revisit and update your business plan as things change, and gather feedback as you go.

5. Failing at marketing.

The hard truth is that no one will buy from you if they don't know who you are. Marketing — that is, direct-mail campaigns, search-engine optimization, blogging, and so forth — should be a key part of your startup from day one. Every successful startup needs to integrate marketing into its budget, and if you want to outsource it to an outside marketing company, make sure you go with an established one.